1. Field of the Invention
The present invention relates to a substrate for a liquid discharging head and a liquid discharging head using the substrate.
2. Description of the Related Art
A liquid discharging apparatus that performs recording by discharging liquid, such as ink, from discharging ports is required to increase the speed of a recording operation and to improve the quality of a recorded image. In particular, to obtain an image of high quality like the quality of photographs, it is effective to increase the resolution of the image. For that purpose, it is necessary to miniaturize droplets to be discharged from a liquid discharging head (e.g., an inkjet recording head) installed in a liquid discharging apparatus such as an inkjet recording apparatus.
To achieve both a higher speed of recording operation and a higher image quality, it is important to use a liquid discharging head having a head substrate on which liquid discharging ports and corresponding energy generating elements for generating energy used to discharge the liquid are arranged in high density.
With recent progress in substrate processing technology, it has been become possible to independently form a plurality of liquid supply ports around one energy generating element. U.S. Patent Application Publication No. 2009/0095708 A1 discloses a configuration in which a plurality of supply ports are provided for one energy generating element.
FIG. 1 illustrates the configuration disclosed in U.S. Patent Application Publication No. 2009/0095708 A1. FIG. 1A is a cross-sectional view of a liquid discharging head, and a resin layer 14 including walls of a flow passage 9 communicating with a discharging port 15 is provided on a substrate 10. Ink supplied from a first supply port 20 and a second supply port 21 is heated via the flow passage 9 by an energy generating element 11 provided on a beam 16, whereby the ink is discharged from the discharging port 15. FIG. 1B is a top view of the liquid discharging head shown in FIG. 1A, and a plurality of supply ports 21 and a plurality of energy generating elements 11 are provided. The energy generating elements 11 are connected to lines 13 for supplying electric power, and the lines 13 are folded back so as to be on beams 16 between the adjacent energy generating elements 11.
However, in the wiring layout of U.S. Patent Application Publication No. 2009/0095708 A1, since the lines 13 are folded back, it is necessary to ensure, between the adjacent energy generating elements 11, areas where the lines 13 are arranged. In this case, it is difficult to densely arrange the energy generating elements because of the areas and the intervals between the lines. Moreover, even if the ink supply characteristic is improved by arranging the second supply ports 21 close to the energy generating elements 11, the improvement is difficult because the folded lines extend between the energy generating elements.
The present invention has been made in view of the above problems, and an object of the invention is to provide a liquid-discharging-head substrate and a liquid discharging head that allow energy generating elements to be densely arranged in an arrangement direction thereof and that can improve a supply characteristic of liquid to the energy generating elements.